1. Technical Field
The present invention relates to an atomic oscillator and a temperature control method of an atomic oscillator.
2. Related Art
An atomic oscillator is known which oscillates on the basis of energy transfer of atoms of an alkali metal such as rubidium or cesium. In general, an operating principle of the atomic oscillator is classified broadly into a method using a double resonance phenomenon based on light and microwaves and a method using a quantum interference effect (CPT: coherent population trapping) based on two types of light beams having different wavelengths.
In any type of atomic oscillator, an alkali metal is sealed in a gas cell together with a buffer gas, a detector provided on a side opposite to the gas cell detects how much light incident on the gas cell is absorbed into the alkali metal to thereby detect atomic resonance, and the detected atomic resonance is output as a reference signal by a control system. As such an atomic oscillator, a configuration is disclosed in which a gas cell is provided on a substrate, and a light source of light (excitation light) and a detecting unit are disposed on both sides of the gas cell (for example, see JP-A-2009-231688).
In addition, since an atomic oscillator using CPT is smaller than an atomic oscillator using a double resonance phenomenon, it is expected that an atomic oscillator is incorporated in various electronic apparatuses, and further reductions in the size and height of the atomic oscillator are desired.
An atomic oscillator is required to be small in size and low in height and to correspond to a wide range of temperature. However, in an atomic oscillator of the related art, there is an increasing concern for a problem such as oscillation characteristics of a gas cell becoming unstable under a high temperature environment.